Update files that don't have the frozen_string_literal comment

prepend_frozen_string_literals

#! /bin/zsh

set -e

rubocop | grep FrozenStringLiteralComment | awk '{ print $1 }' | awk -F ':' '{ print $1 }' | awk '{$1=$1};1' | xargs sed -i "" '1s/^/# frozen_string_literal: true\n\n/'

This also works (and is probably the better way to do it):

git diff --diff-filter=d --name-only $(git merge-base master HEAD) | grep -e ".rb$" -e ".rake$" | xargs -t bundle exec rubocop --enable-pending-cops --autocorrect-all --display-style-guide --force-exclusion

Note that this will only work on projects that use git. The benefit of this approach though is it narrows the scope of changes to only those files that have been updated during a commit.